I wash any new patching material I get to remove the sizing, and then tumble dry with a few tennis balls just to soften it up. Remember that pillow ticking today is not as tightly woven as it was in the past, because feather pillows are nearly nonexistent, hence modern ticking doesn’t need to be tight enough to contain feathers.
I measure material thickness with an old Ames snap mic, always measures with the same pressure, and eliminates pressure guessing.
I don’t buy ticking in large quantities, because cotton deteriorates over time, and exposure to sun light. I am a bloodhound when it comes to sources for linen material in usable thicknesses. You only have to find one good thin linen tablecloth with a cigarette burn, or a red wine stain, to be set for life.
Hungry Horse